Comparison between QSFP-40G-SR4 optical module and QSFP-40G-LR4 optical module

It is easy to see from the above table that the connector types of the two modules are different, and the QSFP-40G-SR4 optical module is commonly used for transmission with multimode optical fiber, and the transmission distance is short; QSFP-40G-LR4 optical module uses single mode optical fiber for transmission, and the transmission distance is longer. The following figures show the working principles of the two modules

Compared with the QSFP-40G-SR4 optical module, the 40G LR4 PSM optical module has the same working principle, both of which convert the photoelectric signal through the laser array; 40G LR4 PSM optical module is suitable for long-distance transmission, and QSFP-40G-SR4 optical module is suitable for short distance transmission.

Compared with the QSFP-40G-LR4 optical module, the 40G LR4 PSM optical module is suitable for long-distance transmission, but the 40G LR4 PSM optical module requires 8 single-mode optical fibers for transmission, while the QSFP-40G-LR4 optical module requires only 2 single-mode optical fibers for transmission.